Louise
You say you have sent your letters to your Job Centre, do you mean the Social Security Agency? I am not completely familiar with the set up of benefits in N. Ireland, but on the mainland, whilst part of the same agency, JC+ and the DWP perform different functions and your request needs to be dealt with by the latter.
Have you contacted the SSA to find out what is going on with your requests, they would normally respond to such a request in a couple of weeks?
You can make the request more formal by making a Subject Access Request, which requires a 40 day response. There is a guide in the Members area that explains how to do this.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
